Deck 6: Wiring Methods

Question 1

What factors cause losses in ferrous raceways in an ac circuit?

Answer 1

Losses in ferrous raceways and enclosures in an alternating current circuit are caused by:
.eddy currents-the current induced in ferrous metals, and
. hysteresis losses-power loss that creates heat in a ferrous metal as a result of the molecules continually reversing.
Eddy currents and hysteresis losses create heat, which damages conductor insulation. Circuits where all of the conductors are close together have lower inductive reactance than circuits where the conductors are spaced farther apart.

Question 2

Compression fittings for EMT are classified as raintight and ____-tight types.

A)snow
B)concrete
C)hail
D)air

Answer 2

B

Question 3

____ boxes are used primarily to install ceiling outlets.

A)Trade size 4 × 4 square
B)Octagonal
C)Trade size 3 × 3 square
D)Masonry

Answer 3

B

Question 4

Where PVC conduit is connected to a box or enclosure, a ____ is recommended.

A)snap switch
B)faceplate
C)male connector
D)box adapter

Question 5

Conduit bodies are often referred to in the trade as "Condulets" and "____."

A)Applets
B)Hindslets
C)Unilets
D)Monolets

Question 6

When pulling three conductors or cables into a raceway, if the ratio of the raceway diameter to the conductor diameter is between 2.8 and 3.2, jamming can occur. With ____ or more conductors or cables, jamming is highly unlikely.

A)four
B)five
C)six
D)seven

Question 7

Voltage drop in a circuit is calculated by multiplying the current flow times the ____.

A)impedance
B)capacitance
C)ampacity
D)inductive reactance

Question 8

When a box contains fittings such as luminaire studs, clamps, or hickeys, the number of conductors permitted in the box is one less for ____ device.

A)every other
B)each type of
C)each individual
D)every two types of

Question 9

The term ____ is defined by the NEC as a channel that is designed expressly for holding wires, cables, or busbars.

A)raceway
B)conduit
C)thread
D)rigid tubing

Question 10

____ is a thin-wall metal raceway that is not permitted to be threaded.

A)Rigid metal conduit (RMC)
B)Intermediate metal conduit (IMC)
C)Electrical metallic tubing (EMT)
D)Unthreaded metal conduit (UMC)

Question 11

Liquidtight flexible nonmetallic conduit marked as ____ has a smooth seamless inner core and cover bonded together and one or more reinforcement layers between the core and covers for layered conduit .

A)LFNC-A
B)LFNC-B
C)LFNC-C
D)LFNC-D

Question 12

Type MC cable is a factory assembly of one or more insulated circuit conductors with or without optical fiber members enclosed in an armor of ____ metal tape, or a smooth or corrugated metallic sheath.

A)interlocking
B)twisted
C)thin
D)flame-retardant

Question 13

The two most popular types of PVC are Schedule 40 and Schedule ____.

A)42
B)60
C)75
D)80

Question 14

On what factors do the conduit and tubing size required for an installation depend?

Question 15

When may liquidtight flexible metallic conduit be used?

Question 16

"Inverse time" refers to the speed of opening of ____.

A)snap switches
B)overcurrent devices
C)solenoids
D)ammeters

Question 17

What is a running thread, and how can it be used?

Question 18

A(n)____ box is used for surface or concealed installations.

A)trade size 4 × 4 square
B)octagonal
C)trade size 3 × 3 square
D)masonry

Question 19

Flexible metal and nonmetallic conduit are commonly used to connect recessed or lay-in ____. When used in this manner, electricians refer to it as a "fixture whip."

A)raceways
B)outlets
C)faceplates
D)luminaires

Question 20

Of what must you be especially careful regarding the depth of the box you are using?